If you’re talking about embedding audio and video files on your website, you have to make sure that you’re defining the file type in the source code, or web browsers may not know what to do with the file. It would also help to make the files as compatible as possible to ensure compatibility with a wide variety of browers. For audio, that would be MP3 files, and for video, that would be Flash video.

As for compatibility of Windows media on the Macintosh: Windows Media files require Windows Media Player. Microsoft has stopped developing WMP for Macintosh, but a company called Flip4Mac makes a free Quicktime plug-in that let’s you play most WMA files. Download it from http://www.flip4mac.com - this will not play back Windows Media 10 files, however.

Alternatively, you can convert those WMA files into MP3 with EasyWMA. $10 from http://www.easywma.com/.

If you’ve purchased those WMA files from a Windows-based music store they will not play on a Mac. You need Windows.